Tactile sensory appreciation is required for learning new movement and refining and maintaining the quality of learned movement via complex feed-forward and feed-back systems. Intact sensory function in the hands is essential for the initiation and execution of refined and dextrous hand, grasp, and finger movements. However, many patients suffering or recovering from medical conditions such as cerebral palsy (CP) and stroke, suffer sensory agnosia, which is a lack of touch sensitivity (or a lack of tactile sensory appreciation), often due to the presence of an underlying sensory impairment. This lack of tactile sensory appreciation can lead to neglect of the limb (and subsequent safety issues) and loss of dexterity. Further, this reduced sensory perception is often limited, or at least more severe, in one limb in which case the other limb can become dominant leading to further neglect or ‘learned non-use’ of the non-dominant limb.
Sensory agnosia often occurs as the result of a stroke, and post-stroke rehabilitation programs have been developed that focus on sensory re-training have proven to be effective (see the systematic review by Schabrun & Hillier, SL 2009, ‘Evidence for the retraining of sensation after stroke: a systematic review’, Clin Rehabil., vol 23, no. 1, pp. 27-39.). These programs have been based on recent developments in the study of the nervous system which have recognised the capacity of the nervous system to modify its organisation and to re-learn and adapt to new experiences —a process known as neuroplasticity. These post-stroke studies have attempted to re-train sensory function through a long and laborious process of intense and focussed attention that requires the subject to manipulate or touch an object and try to identify sensory attributes while their vision is occluded. This requires dedication and devotion to the task over a number of weeks of intense activity and a desire to persist with a frustrating yet potentially beneficial task.
Despite sensory agnosia (a lack of tactile sensory appreciation) being identified as a clinical issue as far back as 1954 (Tizard, JPM et al. 1954, ‘Disturbances of sensation in children with hemiplegia’, J Am Med Assoc., vol 155, no. 7, pp. 628-632.), it is only in recent years that more widespread recognition of sensory agnosia in children with CP has occurred. The prevalence of sensory agnosia in patients has been estimated in studies as being between 40% and 97%. However, whilst awareness of sensory agnosia in CP patients has been improving, attempting to influence tactile sensory perception and address the deficit is not, and thus, there is a shortage of therapies for treating CP patients along with knowledge of their effectiveness. As CP is a life-long condition that patients are typically born with, early intervention during childhood is important to yield long lasting benefits, and any therapies developed should ideally be adapted to suit children. In particular, children can be difficult to enthuse and motivate, particularly when gains can be slow, focussed attention is required, and when they don't fully understand or appreciate the benefits that the activity will bring them. Children typically view therapy as ‘work’ or ‘exercise’ and are not inherently engaged by the activity. Thus, the methods developed for rehabilitating stroke survivors are not generally applicable to children with CP.
One recent approach to physical therapy (motor rehabilitation) has involved the use of computer games to produce a more engaging and enjoyable method to participate in physical therapy. One approach has been to use off the shelf games and gaming systems that use part or all of a game with limited or no modification. These game and gaming systems typically provide continual visual auditory and occasionally haptic (sensory) feedback, increasing the motivation and desire to play and perform (and thus engaging the patients). Another approach has been to design and develop therapeutic gaming systems from scratch. For example, Flores et al. developed virtual reality video games for stroke rehabilitation of elderly patients (Flores et al., “Improving patient motivation in game development for motor deficit rehabilitation”. Proceedings of the International Conference on Advances in Computer Entertainment Technology (2009), Yokohama, Japan: ACM Press).
However, one significant problem with the use of off the shelf games and controllers are that they are designed for use by healthy individuals. As such, the controllers are typically too complex, or require fine motor coordination to use, limiting their use or applicability to people with impaired movement or sensory function. For example, Golomb et al. (Golomb, MR et al. 2011, ‘Maintained Hand Function and Forearm Bone Health 14 Months After an In-Home Virtual-Reality Videogame Hand Telerehabilitation Intervention in an Adolescent With Hemiplegic CP’, J Child Neurol., vol. 26, no. 3, pp. 389-393) developed a custom virtual reality video game tailored to the needs of a 15-year old boy with hemiplegic CP, observing that “. . . the difficulty with many Wiihabilitation [‘Wiihabilitation’ refers to using the Nintendo Wii system for rehabilitation therapy] games, which are designed for healthy individuals, may render them inappropriate for use by some disabled children, and may lead to loss of patient motivation” (pp. 392). In particular, children with CP find nimble, dextrous and coordinated finger movement difficult, particularly when speed and control are required, such as is typically found in most commercial off the shelf games. Further, commercial games typically only provide coarse difficulty controls (eg easy/medium/hard) and limited progress information (eg time played, missions completed) limiting the ability of a therapist to customise treatment to an individual or assess the progress of the treatment.
However, custom designed games are not without problems. One problem with custom designed games is that the interface and game play structure have typically been designed to be as closely comparable to physical therapy as possible therefore, motions and activities in the game are of the same repetitive nature as therapies. Thus, whilst such serious games are able to meet (physically based) therapeutic goals to compliment or replace traditional therapy, they suffer from a lack of variation and have failed to provide engaging or entertaining game experiences important in motivating continued use by patients, especially children. Further, these games have typically been used as physical therapies, in which patients are required to perform gross physical movements with arms and/or shoulders, such as stretching, reaching, extending etc, and thus have not been designed to address underlying sensory agnosia.
There is thus a need to provide a therapeutic method for patients with sensory agnosia or at least to provide patients with a useful alternative to current therapies.